Method of confirming motion parameters apparatus for the same, and motion assisting device

ABSTRACT

The invention provides a method of confirming motion parameters, an apparatus for the same, and a motion assisting device. The invention obtains and utilizes the motion data of a recognized object sampled at each of the sampling time, comprising the acceleration of the recognized object sampled by a tri-axial accelerometer, the angular velocity of the recognized object sampled by a tri-axial gyroscope, and the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system sampled by a tri-axial magnetometer. Feedback calculation is utilized to obtain an actual acceleration at each sampling time from the motion original time to the motion end time, and the actual acceleration is obtained by reducing the acceleration of gravity from the acceleration sampled by a tri-axial accelerometer. The invention reduces the complexity of the system, and the accuracy is less affected by environmental factors, particularly light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Chinese Patent Application No.201110111559.8 filed on Apr. 29, 2011, the disclosure of which isincorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to motion recognition technology, andparticularly to a method of confirming motion parameters, an apparatusfor the same, and a motion assisting device.

BACKGROUND OF THE DISCLOSURE

Path and stance recognition for a spatial accelerated motion refers todetecting position and intersection angles at each time in the movingprocess of an object, and obtaining the real-time velocity of theobject. The technique of path and stance recognition for the spatialaccelerated motion can be widely applicable in combination to human bodyaction for detection of human body action in areas such as sports,games, movie technology, medical surgery simulation or action skilltraining.

Currently, the existing motion recognition technology focuses on thefollowing issues:

(1) utilizing a combination of ultrared array and microelectromechanicalsystem (MEMS) sensors to detect a three-dimensional motion.

(2) utilizing a combination of visual and MEMS sensors to enhanceaccuracy to motion recognition to a hand motion.

(3) utilizing visualization methods to sample information includingfull-body three-dimensional motions, facial motions and voice by usingRGB cameras, depth sensors and microphone arrays.

However, the three focused issues utilize visualization methods, andaccuracy would be greatly affected by environmental factors,particularly light.

SUMMARY OF THE DISCLOSURE

The disclosure provides a method of confirming motion parameters, anapparatus for the same, and a motion assisting device, for maintainingthe accuracy by reducing the effect of environmental factors.

Specifically, the method of confirming motion parameters provided by thedisclosure comprises:

(S1) obtaining and storing motion data at each sampling time, the motiondata comprising: acceleration of a recognized object, angular velocityof the recognized object, and an angle of the recognized objectcorresponding to a three-dimensional geomagnetic coordinate system;

(S2) perform ling motion static detection utilizing the accelerationstored at each of the sampling time to confirm a motion original timet_(o) and a motion end time t_(e) of a motion;

(S3) confirming an original stance matrix T_(m) ^(bInit) correspondingto the three-dimensional geomagnetic coordinate system at the motionoriginal time t_(o) according to the angle stored at the motion originaltime t_(o); and

(S4) using each of the sampling time sequentially as a current samplingtime to perform steps S41 to S43:

(S41) confirming and recording a stance change matrix T_(bInit) ^(bCur)from the current sampling time to the motion original time t_(o)according to the angular velocity stored at the current sampling timeand at a previous sampling time, and a stance change matrix T_(bInit)^(bPre) from the previous sampling time to the motion original timet_(o);

(S42) confirming a stance matrix T_(m) ^(bCur) at the current samplingtime corresponding to the three-dimensional geomagnetic coordinatesystem as T_(m) ^(bCur)=T_(bInit) ^(bCur); and

(S43) obtaining an actual acceleration a_(m) ^(Mcur) at the currentsampling time by adjusting the acceleration a^(Cur) at the currentsampling time utilizing the stance matrix T_(m) ^(bCur) to reduces anacceleration of gravity {right arrow over (g)} from the accelerationa^(Cur) at the current sampling time.

The apparatus for confirming motion parameters provided by thedisclosure comprises:

a motion data obtaining unit to obtain motion data at each sampling timeof a motion, the motion data comprising: acceleration of a recognizedobject sampled by a tri-axial accelerometer, angular velocity of therecognized object sampled by a tri-axial gyroscope, and an angle of therecognized object corresponding to a three-dimensional geomagneticcoordinate system sampled by a tri-axial magnetometer;

a data storage unit to store the motion data;

a motion static detecting unit to perform motion static detectionutilizing the acceleration stored in the data storage unit at each ofthe sampling time to confirm a motion original time t_(o) and a motionend time t_(e) of the motion;

an original stance confirming unit to confirm an original stance matrixT_(m) ^(bInit) corresponding to the three-dimensional geomagneticcoordinate system at the motion original time t_(o) according to theangle stored in the data storage unit at the motion original time t_(o);and

a motion parameter confirming unit to confirm the acceleration at eachof the sampling time by using the sampling time after the motionoriginal time t_(o) and before the motion end time t_(e) sequentially asa current sampling time; wherein the motion parameter confirming unitcomprises:

a stance change confirming module to confirm and record a stance changematrix T_(bInit) ^(bCur) from the current sampling time to the motionoriginal time t_(o) according to the angular velocity stored in the datastorage unit at the current sampling time and at a previous samplingtime, and a stance change matrix T_(bInit) ^(bPre) from the previoussampling time to the motion original time t_(o);

a real-time stance confirming module to confirm a stance matrix T_(m)^(bCur) at the current sampling time corresponding to thethree-dimensional geomagnetic coordinate system as T_(m)^(bCur)=T_(bInit) ^(bCur); and

a degravitation module to obtain an actual acceleration a_(m) ^(Mcur) atthe current sampling time by adjusting the acceleration a^(Cur) at thecurrent sampling time utilizing the stance matrix T_(m) ^(bCur) toreduces an acceleration of gravity {right arrow over (g)} from theacceleration a^(Cur) at the current sampling time.

The motion assisting device provided by the invention comprises a sensordevice, and the aforementioned apparatus for confirming motionparameters.

The sensor device is configured to sample the motion data of therecognized object at each of the sampling time, the motion datacomprising: the acceleration of the recognized object, the angularvelocity of the recognized object, and the angle of the recognizedobject corresponding to a three-dimensional geomagnetic coordinatesystem.

According to the disclosed technology, the method, apparatus and themotion assisting device in the present disclosure do not rely onvisualization methods, and the accuracy would be less affected byenvironmental factors, particularly light.

To improve understanding of the invention, the techniques employed bythe present disclosure to achieve the foregoing objectives,characteristics and effects thereof are described hereinafter by way ofexamples with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a schematic view of the structure of the recognition systemin an embodiment of the disclosure;

FIG. 1 b is a schematic view of the motion assisting device in anembodiment of the disclosure;

FIG. 2 is a schematic view of an angle output by a tri-axialmagnetometer in an embodiment of the disclosure;

FIG. 3 is a schematic view of the format of a data packet transmitted bya processor in an embodiment of the disclosure;

FIG. 4 is a flowchart of the method of confirming motion parametersprovided in an embodiment of the disclosure; and

FIG. 5 is a schematic view of the structure the apparatus for confirmingmotion parameters in an embodiment of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

To achieve the foregoing objectives, technical characteristics andadvantages, the techniques employed by the present disclosure aredescribed hereinafter in detail by way of embodiments with reference tothe accompanying drawings.

An embodiment of the disclosure is shown in FIG. 1 a as a recognitionsystem, which comprises: a microelectromechanical system (MEMS) sensordevice 100, a processor 110, data transmit interface 120, and anapparatus for confirming motion parameter 130. The recognition systemcan further comprise: a motion recognizing device 140, a parameterdisplay device 150, and an expert evaluation device 160. The MEMS sensordevice 100, the processor 110, and the data transmit interface 120 canbe packed as a terminal device provided on the recognized object. Forexample, the MEMS sensor device 100, the processor 110, and the datatransmit interface 120 can be packed as a portable motion detectiondevice provided on the recognized object, such as the gloves of a ballplayer, the golf club, or a joint point. Generally, the weight of theportable motion detection device can be dozens of grams and thusignorable without disturbing the motion of the recognized object.

In the embodiment, the MEMS sensor device 100 may comprise a tri-axialaccelerometer 101, a tri-axial gyroscope 102, and a tri-axialmagnetometer 103.

The tri-axial accelerometer 101 is configured to sample acceleration ofthe recognized object at each sampling time. The acceleration is thethree-dimensional acceleration, which includes acceleration alongX-axis, Y-axis and Z-axis at each sampling time.

The tri-axial gyroscope 102 is configured to sample angular velocity ofthe recognized object at each sampling time. Similarly, the angularvelocity is the three-dimensional angular velocity, which includesangular velocity along X-axis, Y-axis and Z-axis at each sampling time.

The tri-axial magnetometer 103 is configured to sample the angle of therecognized object corresponding to a three-dimensional geomagneticcoordinate system. At each sampling time, the angle data include: Roll,Yaw and Pitch, in which Roll is the angle between the X-axis of therecognized object and the XY plane of the three-dimensional geomagneticcoordinate system, Yaw is the angle between the projecting vector of theY-axis of the recognized object onto the XY plane of thethree-dimensional geomagnetic coordinate system and the Y-axis of thethree-dimensional geomagnetic coordinate system, and Pitch is the anglebetween the Y-axis of the recognized object and the the XY plane of thethree-dimensional geomagnetic coordinate system. As shown in FIG. 2,Xmag, Ymag and Zmag are the X-axis, Y-axis and Z-axis of thethree-dimensional geomagnetic coordinate system, and Xsen, Ysen and Zsenare the X-axis, Y-axis and Z-axis of the recognized object.

The processor 110 retrieves motion data sampled by the tri-axialaccelerometer 101, the tri-axial gyroscope 102, and the tri-axialmagnetometer 103 of the MEMS sensor device 100, and transmit the motiondata to the motion parameter confirming device 130 according topredetermined transfer protocol. FIG. 3 shows one format of the datapacket of the motion data transmitted by the processor, in which themark field can include verification information to ensure thecompleteness and safety of the data, and the header field can includeprotocol header applied in transmission of the motion data.

Furthermore, the processor 110 can be utilized to receive configurationinstructions from the data transmit interface 120, interpret theconfiguration instructions, configure the MEMS sensor device 100according to the interpreted data, such as sampling accuracy, samplingfrequency and range, and perform calibration of the motion datareceived. Preferably, the processor 110 can be a low power processor toincrease endurance time.

The tri-axial accelerometer 101, the tri-axial gyroscope 102, and thetri-axial magnetometer 103 of the MEMS sensor device 100 can beconnected to the processor 110 by serial bus or AD interface.

The data transmit interface 120 can support wired communication orwireless communication. Wired interface can be protocols such as USB,COM, LPT, or live line, and wireless interface can be Bluetooth or IRDA.In FIG. 1 a, the data transmit interface 120 of the embodiment has a USBinterface 121 and/or a Bluetooth module 122. The USB interface 121 canenable power charge of the terminal device with the MEMS sensor device100, the processor 110, and the data transmit interface 120 packedtogether and perform two-way communication to other devices. TheBluetooth module 122 can enable two-way communication from the terminaldevice to the Bluetooth master device.

The apparatus for confirming motion parameter 130, the motionrecognizing device 140, the parameter display device 150, and the expertevaluation device 160 can be connected to the processor 110 via the USBinterface (not shown in FIG. 1 a), or can serve as the Bluetooth masterdevice and be connected to the processor 110 via the Bluetooth module122.

The apparatus for confirming motion parameter 130 is configured toconfirm motion parameters, such as acceleration information, velocityinformation, position information, and stance information, according tothe motion data received.

The motion recognizing device 140 can be utilized to recognize the typeof the motion according to the motion parameters confirmed by theapparatus for confirming motion parameter 130, and to extract the motionparameters of the motion of a certain type of sport.

The parameter display device 150 is configured to display the motionparameters confirmed by the apparatus for confirming motion parameter130 in a certain format (the connection is not shown in the figures) orthe motion parameters extracted by the motion recognizing device 140 ina certain format, such as showing a three-dimensional path of theposition of the recognized object, or velocity information of therecognized object in the format of a table or a line chart. Theparameter display device 150 can be any terminal device with displayfunction, such as a computer, a cell phone, or a PDA.

The expert evaluation device 160 is configured to evaluate the motionaccording to the motion parameters confirmed by the apparatus forconfirming motion parameter 130 (the connection is not shown in thefigures) or the motion parameters extracted by the motion recognizingdevice 140. The evaluation can be from a real expert or an automatedevaluation according to preset motion parameter database.

It should be noted that, in an embodiment, the MEMS sensor device 100and the apparatus for confirming motion parameter 130 can be packed as amotion assisting device, as shown in FIG. 1 b. The apparatus forconfirming motion parameter 130 can directly obtain the motion datasampled by the MEMS sensor device 100 and confirm the motion parametersof the recognized object at each of the sampling time, and transmit themotion parameters to the motion recognizing device 140 to perform motionrecognition.

In the motion assisting device, the processor 110 can also retrieve themotion data from the MEMS sensor device 100 according to a predeterminedfrequency, and transmit the motion data to the apparatus for confirmingmotion parameter 130 under the transfer protocol.

Furthermore, the data transmit interface 120 can be provided as aninterface to connect to the apparatus for confirming motion parameter130. Similarly, the data transmit interface 120 can also be a USBinterface 121 or a Bluetooth module 122. The data transmit interface 120can transmit the motion parameters confirmed by the apparatus forconfirming motion parameter 130 to other devices, such as the motionrecognizing device, the parameter display device or the expertevaluation device.

Alternatively, the data transmit interface 120 can also be disposedbetween the processor and the apparatus for confirming motion parameter130 in the way as shown in FIG. 1 a.

Based on the aforementioned system, the method of confirming motionparameters utilized in the apparatus for confirming motion parameters130 can be described according to the following embodiment. As shown inFIG. 4, the method of confirming motion parameters comprises thefollowing steps:

Step 401: obtaining the motion data at each of the sampling time, themotion data includes: the acceleration of the recognized object sampledby the tri-axial accelerometer, the angular velocity of the recognizedobject sampled by the tri-axial gyroscope, and the angle of therecognized object corresponding to a three-dimensional geomagneticcoordinate system sampled by the tri-axial magnetometer.

In obtaining the motion data at each sampling time, if the samplingfrequency of the MEMS sensor device is not high enough, the motion dataobtained can be processed by interpolation processing, such as linearinterpolation or spline interpolation, to enhance the calculationaccuracy of the motion parameters of acceleration, velocity andposition.

Step 402: pre-processing the motion data obtained.

The pre-processing of the step is to perform filtering to the motiondata to reduce the noise of the motion data sampled by the MEMS sensordevice. Various filtering approaches can be utilized. For example, 16point Fast Fourier Transform (FFT) filtering can be used. The specificapproach of filtering is not limited.

The interpolation processing and pre-processing are not necessarilyperformed in a fixed order. The processing can be performed in anysequence. Alternatively, it is optional to perform only one of theprocessing.

Step 403: performing data calibration to the pre-processed motion data.

The step mainly performs calibration to the acceleration sampled by thetri-axial accelerometer. The tri-axial accelerometer has a zero drift{right arrow over (ω)}_(o), and the acceleration obtained at eachsampling time is reduced by the zero drift {right arrow over (ω)}_(o) toobtain the calibrated acceleration at each sampling time. The zero drift{right arrow over (ω)}_(o) of the tri-axial accelerometer can beobtained by sampling acceleration to a nonmoving object.

The steps 402 and 403 are preferred steps of the embodiment of theinvention. However, the steps 402 and 403 can be skipped and the motiondata obtained in step 401 can be cached directly.

Step 404: caching the calibrated motion data at each sampling time.

The most recently obtained number N of the motion data is saved to thecache. That is, the cached motion data includes: the motion data at thelatest sampling time to the motion data at the earlier N−1 samplingtime. The motion data of the earliest sampling time overflows when themotion data of a new sampling time is saved to the cache. Preferably, Ncan be an integer of 3 or higher, and generally is an integer power of2, such as 16 or 32 to maintain a caching length of 0.1 s˜0.2 s ofmotion data in the cache. The data structure of the cache is a queue inthe order of the sampling time, with the motion data of the latestsampling time at the end of the queue.

It should be noted that, in the embodiment the calibrated motion data iscached, but it can also be stored in any other type of storage devices.

Step 405: performing motion static detection utilizing acceleration ateach of the sampling time to confirm an original time t_(o) and an endtime t_(e) of the motion.

The original time t_(o) is the critical sampling time from the nonmovingcondition to the moving condition, and the end time t_(e) is thecritical sampling time from the moving condition to the nonmovingcondition.

Judgment is performed according to predetermined motion time confirmingtactics to each of the sampling time in sequence of the sampling time.If at the sampling time to the predetermined motion time confirmingtactics are satisfied and at the sampling time to−1 the predeterminedmotion time confirming tactics are not satisfied, the sampling time tois confirmed as the original time. If at the sampling time t_(e) thepredetermined motion time confirming tactics are satisfied and at thesampling time t_(e)+1 the predetermined motion time confirming tacticsare not satisfied, the sampling time t_(e) is confirmed as the end time.

Specifically, the predetermined motion time confirming tactics maycomprise: confirming one of the sampling time t_(x) as motion time if amodulated variance a_(v) of the acceleration from a number T of thesampling time before the sampling time t_(x) is larger than or equal toa predetermined acceleration variance threshold and a modulatedacceleration a_(o) at the sampling time t_(x) is larger than or equal toa predetermined motion acceleration threshold. In other words, if at acertain sampling time the predetermined motion time confirming tacticsare satisfied, the sampling time is considered in a moving condition;otherwise it is considered in a nonmoving condition. T is apredetermined positive integer.

The predetermined motion time confirming tactics may effectively filtershock in a short time and prevent from a cutoff of a complete motion byshort-term standstill and pause actions. The value of the predeterminedacceleration variance threshold and the predetermined motionacceleration threshold can be flexible according to the degree of themotion of the recognized object. When the motion of the recognizedobject is more violent, the value of the predetermined accelerationvariance threshold and the predetermined motion acceleration thresholdcan be set higher.

The sampling time between the original time t_(o) and the end time t_(e)in the cache is treated in sequence as the current sampling time toperform steps 406 to 411.

Step 406: confirming the original stance matrix T_(m) ^(bInit)corresponding to the geomagnetic coordinate system at the original timet_(o) of the motion according to the motion data sampled by thetri-axial magnetometer in the cache.T _(m) ^(bInit) =[X _(bt) ₀ ,Y _(bt) ₀ ,Z _(bt) ₀ ]  (1)wherein:

$X_{{bt}_{0}} = \begin{bmatrix}{{{\sin\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}} + {{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}}} \\{{{\sin\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}}} \\{{- {\sin\left( {Roll}_{t_{0}} \right)}}{\cos\left( {Pitch}_{t_{0}} \right)}}\end{bmatrix}$ ${Y_{{bt}_{0}} = \begin{bmatrix}{{\cos\left( {Pitch}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}} \\{{\cos\left( {Pitch}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}} \\{\sin\left( {Pitch}_{t_{0}} \right)}\end{bmatrix}},{and}$ $Z_{{bt}_{0}} = \begin{bmatrix}{{{\sin\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}}} \\{{{- {\sin\left( {Roll}_{t_{0}} \right)}}{\sin\left( {Yaw}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}}} \\{{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Pitch}_{t_{0}} \right)}}\end{bmatrix}$

Roll_(t) ₀ , Yaw_(t) ₀ and Pitch_(t) ₀ are the angles sampled at thesampling time to by the tri-axial magnetometer.

Step 407: when the recognized object is in the moving condition,confirming the stance change matrix T_(bPre) ^(bCur) from the previoussampling time to the current sampling time according to the angularvelocity data sampled at the current sampling time and the previoussampling time by the tri-axial gyroscope.

Specifically, the angular velocity data sampled by the tri-axialgyroscope at the previous sampling time is w_(P)=[ω_(Px), ω_(Py),ω_(Pz)]^(T), and the angular velocity data at the current sampling timeis w_(C)=[ω_(Cx), ω_(Cy), ω_(Cz)]^(T). The time interval betweenadjacent sampling time is t, and the stance change matrix T_(bPre)^(bCur) from the previous sampling time to the current sampling time canbe confirmed as T_(bPre) ^(bCur)=R_(Z)R_(Y)R_(X).

R_(Z), R_(Y), R_(X) are the stance change matrices of ω_(P),respectively rotating (ω_(Pz)+ω_(Cz))t/2, (ω_(Py)+ω_(Cy))t/2, and(ω_(Px)+ω_(Cx))t/2 around the Z-axis, Y-axis, and X-axis.

Step 408: confirming and recording the stance change matrix T_(bInit)^(bCur) from the current time to the original time t_(o) according tothe stance change matrix T_(bInit) ^(bPre) from the previous time to theoriginal time t_(o) and the stance change matrix T_(bPre) ^(bCur).

In the motion with the original time t_(o), the stance change matrixfrom any of the sampling time to the original time t_(o) will berecorded. Thus, with the stance change matrix T_(bInit) ^(bPre) from theprevious time retrieved, the stance change matrix T_(bPre) ^(bCur) ofthe current time can be:T _(bInit) ^(bCur) =T _(bInit) ^(bPre) T _(bPre) ^(bCur)  (2)

Step 409: confirming the stance matrix T_(m) ^(bCur) at the currentsampling time corresponding to the three-dimensional geomagneticcoordinate system as T_(m) ^(bCur)=T_(m) ^(bInit)T_(bInit) ^(hCur).

According to the steps 407, 408 and 409, the stance matrix T_(m) ^(bCur)at the current sampling time corresponding to the three-dimensionalgeomagnetic coordinate system is obtained by a “feedback” type ofiterative calculation, which is shown as

$T_{m}^{bCur} = {T_{m}^{bInit}\underset{x = {Init}}{\coprod\limits^{{Cur} - 1}}{T_{b{({x + 1})}}^{bx}.}}$The terms Cur is the current sampling time, Init is the original timet_(o), and T_(b(x+1)) ^(bx) is the stance change matrix from samplingtime x to sampling time x+1.

Step 410: obtaining the actual acceleration a_(m) ^(Mcur) at the currentsampling time according to the formula a_(m) ^(Mcur)=T_(m)^(bCur)a^(cur)−{right arrow over (g)}, which reduces the acceleration ofgravity {right arrow over (g)} from the acceleration a^(Cur) at thecurrent sampling time.

The acceleration of gravity {right arrow over (g)} of thethree-dimensional geomagnetic coordinate system can be obtained by anonmoving object.

Specifically, the tri-axial accelerometer can be utilized to sample anonmoving object with M numbers of consecutive sampling time. Thus, themean value of the acceleration of gravity obtained with the M numbers ofconsecutive sampling time can be the acceleration of gravity {rightarrow over (g)} of the three-dimensional geomagnetic coordinate system.The acceleration of gravity {right arrow over (g)} can be confirmedaccording to formula (3):

$\begin{matrix}{\overset{\rightarrow}{g} = {\frac{1}{M}{\sum\limits_{j = i}^{i + M}{\overset{\rightarrow}{a}}_{mj}}}} & (3)\end{matrix}$

wherein:

M is a predetermined positive integer,

i is the original sampling time for sampling of the nonmoving object,and{right arrow over (a)}=T _(mj) ^(b) {right arrow over (a)} _(bj)  (4)

{right arrow over (a)}_(bj) is the acceleration sampled by the tri-axialaccelerometer at the sampling time j, and T_(mj) ^(b) is the stancematrix of the nonmoving object at the sampling time j. According to theangle confirmed by the trial-axial accelerometer at the sampling time j,T_(mj) ^(b) is:T _(mj) ^(b) =[X _(bj) ,Y _(bj) ,Z _(bj)]  (5)

wherein:

$X_{bj} = \begin{bmatrix}{{{\sin\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}} + {{\cos\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}}} \\{{{\sin\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}}} \\{{- {\sin\left( {Roll}_{j} \right)}}{\cos\left( {Pitch}_{j} \right)}}\end{bmatrix}$ ${Y_{bj} = \begin{bmatrix}{{\cos\left( {Pitch}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}} \\{{\cos\left( {Pitch}_{t_{0}} \right)}{\cos\left( {Yaw}_{j} \right)}} \\{\sin\left( {Pitch}_{j} \right)}\end{bmatrix}},{and}$ $Z_{bj} = \begin{bmatrix}{{{\sin\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}}} \\{{{- {\sin\left( {Roll}_{j} \right)}}{\sin\left( {Yaw}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}}} \\{{\cos\left( {Roll}_{j} \right)}{\cos\left( {Pitch}_{j} \right)}}\end{bmatrix}$

Roll_(j), Yaw_(j) and Pitch_(j) are the angles sampled at the samplingtime j by the tri-axial magnetometer.

Step 411: performing integral to the actual acceleration from theoriginal time t_(o) to the current sampling time to obtain the real-timevelocity at the current sampling time, and performing integral to thereal-time velocity from the original time t_(o) to the current samplingtime to obtain the position at the current sampling time.

The technique to obtain real-time velocity and position in the step iswell-known, and description of the technique will be hereafter omitted.

Thus, at least one of the acceleration, real-time velocity and positionbetween the original time t_(o) and the end time t_(e) can be saved inthe database as the motion parameters of the motion.

In the aforementioned process, if the time interval between the end timeof a motion and the original time of a next motion is shorter than apredetermined time period threshold, the two separate motions would beconsidered one continuous motion, and “connecting” of the motions mustbe performed. That is, if the time interval between the original timet_(o) confirmed by the step 405 and the end time t′ of the previousmotion is shorter than the predetermined time period threshold, thestance matrix of t′ serves as the original stance matrix T_(m) ^(bInit)at at the original time t_(o). Otherwise, the original stance matrixT_(m) ^(bInit) at the original time t_(o) is confirmed according toformula (1).

The apparatus for confirming motion parameters corresponding to theaforementioned method of confirming motion parameters can be hereafterdescribed in detail. As shown in FIG. 5, the apparatus comprises: amotion data obtaining unit 500, a data storage unit 510, a motion staticdetecting unit 520, an original stance confirming unit 530, and a motionparameter confirming unit 540.

The motion data obtaining unit 500 is configured to obtain motion dataat each sampling time of a motion and send the motion data to the datastorage unit 510. The motion data comprises: acceleration of arecognized object sampled by a tri-axial accelerometer, angular velocityof the recognized object sampled by a tri-axial gyroscope, and an angleof the recognized object corresponding to a three-dimensionalgeomagnetic coordinate system sampled by a tri-axial magnetometer.

The data storage unit 510 is configured to store the motion data.

Specifically, the data storage unit 510 stores most recently obtainednumber N of the motion data to a cache. N is an integer of 3 or higher,and the motion data in the cache is in an order of the sampling timewith the motion data of a latest sampling time at an end of a queue inthe cache. In other words, the data storage unit 510 stores motion datafrom the latest sampling time to the previous N−1 sampling time to thecache.

The motion static detecting unit 520 is configured to perform motionstatic detection utilizing the acceleration stored in the data storageunit 510 at each of the sampling time to confirm a motion original timet_(o) and a motion end time t_(e) of the motion.

The original stance confirming unit 530 is configured to confirm anoriginal stance matrix T_(m) ^(bInit) corresponding to thethree-dimensional geomagnetic coordinate system at the motion originaltime t_(o) according to the angle stored in the data storage unit 510 atthe motion original time t_(o).T _(m) ^(bInit) =[X _(bt) ₀ ,Y _(bt) ₀ ,Z _(bt) ₀ ]  (1)

wherein:

$X_{{bt}_{0}} = \begin{bmatrix}{{{\sin\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}} + {{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}}} \\{{{\sin\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}}} \\{{- {\sin\left( {Roll}_{t_{0}} \right)}}{\cos\left( {Pitch}_{t_{0}} \right)}}\end{bmatrix}$ ${Y_{{bt}_{0}} = \begin{bmatrix}{{\cos\left( {Pitch}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}} \\{{\cos\left( {Pitch}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}} \\{\sin\left( {Pitch}_{t_{0}} \right)}\end{bmatrix}},{and}$ $Z_{{bt}_{0}} = \begin{bmatrix}{{{\sin\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\sin\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}}} \\{{{- {\sin\left( {Roll}_{t_{0}} \right)}}{\sin\left( {Yaw}_{t_{0}} \right)}} - {{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Yaw}_{t_{0}} \right)}{\sin\left( {Pitch}_{t_{0}} \right)}}} \\{{\cos\left( {Roll}_{t_{0}} \right)}{\cos\left( {Pitch}_{t_{0}} \right)}}\end{bmatrix}$

Roll_(t) ₀ , Yaw_(t) ₀ and Pitch_(t) ₀ are the angles sampled at thesampling time to by the tri-axial magnetometer.

The motion parameter confirming unit 540 is configured to confirm theacceleration at each of the sampling time by using the sampling timeafter the motion original time t_(o) and before the motion end timet_(e) sequentially as a current sampling time.

Specifically, the motion parameter confirming unit 540 comprises: astance change confirming module 541, a real-time stance confirmingmodule 542 and a degravitation module 543.

The stance change confirming module 541 is configured to confirm andrecord a stance change matrix T_(bInit) ^(bCur) from the currentsampling time to the motion original time t_(o) according to the angularvelocity stored in the data storage unit at the current sampling timeand at a previous sampling time, and a stance change matrix T_(bInit)^(bPre) from the previous sampling time to the motion original timet_(o).

The real-time stance confirming module 542 is configured to confirm astance matrix T_(m) ^(bCur) at the current sampling time correspondingto the three-dimensional geomagnetic coordinate system as T_(m)^(bCur)=T_(m) ^(bInit)T_(bInit) ^(bCur).

The degravitation module 543 is configured to obtain an actualacceleration a_(m) ^(Mcur) at the current sampling by adjusting theacceleration a^(Cur) at the current sampling time utilizing the stancematrix T_(m) ^(bCur) to reduces an acceleration of gravity {right arrowover (g)} from the acceleration a^(Cur) at the current sampling time.

Furthermore, the apparatus may further comprise at least one of apreprocessing unit 550 and a filtering processing unit 560. The twounits do not have a priority of process or a fixed order in processing,and processing of each unit can be performed in any sequence. FIG. 1 ashows an embodiment including both units.

The preprocessing unit 550 is configured to perform interpolationprocessing to the motion data obtained by the motion data obtaining unit500 and sent to the data storage unit 510. By the preprocessing unit550, calculation accuracy in further calculation of acceleration,velocity and position can be enhanced even if the MEMS sensor does nothave high sampling frequency. The interpolation processing utilized canbe but not limited to linear interpolation or spline interpolation.

The filtering processing unit 560 is configured to perform filteringprocessing to the motion data obtained by the motion data obtaining unit500 and sent to the data storage unit 510. Various filtering approachescan be utilized. For example, 16 point Fast Fourier Transform (FFT)filtering can be used. The specific approach of filtering is notlimited.

The tri-axial accelerometer may have a problem with inaccuracy insampling the acceleration due to the zero drift. Thus, the apparatus mayfurther comprise a data calibration unit 570 to perform data calibrationto the motion data obtained by the motion data obtaining unit 500 andsent to the data storage unit 510 utilizing a zero drift {right arrowover (ω)}₀ of the tri-axial accelerometer sampling the acceleration. Inother words, the acceleration obtained at each sampling time is reducedby the zero drift {right arrow over (ω)}₀ to obtain the calibratedacceleration at each sampling time.

In performing motion static detection, the motion static detecting unit520 may perform judgment according to predetermined motion timeconfirming tactics to each of the sampling time in sequence of thesampling time. If at the sampling time t_(o) the predetermined motiontime confirming tactics are satisfied and at the sampling time t_(o)−1the predetermined motion time confirming tactics are not satisfied, thesampling time t_(o) is confirmed as the motion original time; and if atthe sampling time t_(e) the predetermined motion time confirming tacticsare satisfied and at the sampling time t_(e)+1 the predetermined motiontime confirming tactics are not satisfied, the sampling time t_(e) isconfirmed as the motion end time.

The predetermined motion time confirming tactics can be: confirming oneof the sampling time t_(x) as motion time if a modulated variance a_(v)of the acceleration from a number T of the sampling time before thesampling time t_(x) is larger than or equal to a predeterminedacceleration variance threshold and a modulated acceleration a₀ at thesampling time t_(x) is larger than or equal to a predetermined motionacceleration threshold. The number T is a predetermined positiveinteger.

In an actual motion, a shock may exist during the motion period tocreate a temporary change of status. However, the motion is still acontinuous motion. In order to deal with this problem, the originalstance confirming unit 530 may further comprise a motion intervalcomparing module 531 and an original stance confirming module 532.

The motion interval comparing module 531 is configured to compare a timeinterval between the motion original time t_(o) and a last motionoriginal time t′ to a predetermined time period threshold and determinewhether the time interval is shorter than the predetermined time periodthreshold.

The original stance confirming module 532 is configured to confirm theoriginal stance matrix T_(m) ^(bInit) corresponding to thethree-dimensional geomagnetic coordinate system at the motion originaltime t_(o) according to the angle stored in the data storage unit at themotion original time to if the time interval is not shorter than thepredetermined time period threshold, and to confirm a stance matrixcorresponding to the three-dimensional geomagnetic coordinate system atthe last motion original time t′ as the original stance matrix T_(m)^(bInit) corresponding to the three-dimensional geomagnetic coordinatesystem at the motion original time t_(o) if the time interval is shorterthan the predetermined time period threshold.

In the apparatus, the stance change confirming module 541 may furthercomprise a first stance change confirming submodule 5411 and a secondstance change confirming submodule 5412.

The first stance change confirming submodule 5411 is configured toconfirm the stance change matrix T_(bPre) ^(bCur) from the previoussampling time to the current sampling time according to the angularvelocity data stored at the current sampling time and at the previoussampling time in the data storage unit 510.

Specifically, the first stance change confirming submodule 5411 confirmsthe angular velocity data w_(P) stored the previous sampling time isw_(P)=[ω_(Px), ω_(Py), ω_(Pz)]^(T) and the angular velocity data w_(C)at the current sampling time is w_(C)=[ω_(Cx), ω_(Cy), ω_(Cz)]^(T), andconfirms the stance change matrix T_(bPre) ^(bcur) from the previoussampling time to the current sampling time as T_(bPre)^(bCur)=R_(ZY)R_(Y)R_(X), wherein R_(Z) is a stance change matrix of theangular velocity data w_(P) rotating (ω_(Pz)+ω_(Cz))t/2 around a Z-axis,R_(Y) is a stance change matrix of the angular velocity data w_(P)rotating (ω_(Py)+ω_(Cy))t/2, around a Y-axis, R_(X) is a stance changematrix of the angular velocity data w_(P) rotating (ω_(Px)+ω_(Cx))t/2around a X-axis, and t is a time interval between adjacent samplingtime.

The second stance change confirming submodule 5412 is configured toobtain the stance change matrix T_(bInit) ^(bPre) from the previoussampling time to the motion original time t_(o), and confirming a stancechange matrix T_(bInit) ^(bCur) from the current sampling time to themotion original time t_(o) as T_(bInit) ^(bPre)T_(bPre) ^(bCur).

The degravitation module 543 may obtain the actual acceleration a_(m)^(Mcur) at the current sampling time as a_(m) ^(Mcur)=T_(m)^(bCur)a^(cur)−{right arrow over (g)}. {right arrow over (g)} is theacceleration of gravity under the three-dimensional geomagneticcoordinate system.

To confirm the acceleration of gravity {right arrow over (g)} under thethree-dimensional geomagnetic coordinate system, the apparatus mayfurther comprise gravitational motion parameter confirming unit 580. Thegravitational motion parameter confirming unit 580 may comprise a dataobtaining module 581 and a gravity acceleration confirming module 582.

The data obtaining module 581 is configured to obtain the accelerationand the angle sampled from a nonmoving object with M numbers ofconsecutive sampling time. That is, the tri-axial accelerometer and thetri-axial magnetometer are used to sample the nonmoving object for thedata obtaining module 581 to obtain the acceleration and the angle withM numbers of consecutive sampling time.

The gravity acceleration confirming module 582 is configured to confirmthe acceleration of gravity {right arrow over (g)} under thethree-dimensional geomagnetic coordinate system as

${\overset{\rightarrow}{g} = {\frac{1}{M}{\sum\limits_{j = i}^{i + M}{\overset{\rightarrow}{a}}_{mj}}}},$wherein M is a predetermined positive integer, i is an original samplingtime for sampling of the nonmoving object, {right arrow over(a)}_(mj)=T_(mj) ^(b){right arrow over (a)}_(bj), {right arrow over(a)}_(bj) is the acceleration sampled from the nonmoving object at oneof the sampling time j, and T_(mj) ^(b) is a stance matrix of thenonmoving object at the sampling time j confirmed by the angle of thenonmoving object at the sampling time j.T _(mj) ^(b) =[X _(bj) ,Y _(bj) ,Z _(bj)]  (5)

wherein:

$X_{bj} = \begin{bmatrix}{{{\sin\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}} + {{\cos\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}}} \\{{{\sin\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}}} \\{{- {\sin\left( {Roll}_{j} \right)}}{\cos\left( {Pitch}_{j} \right)}}\end{bmatrix}$ ${Y_{bj} = \begin{bmatrix}{{\cos\left( {Pitch}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}} \\{{\cos\left( {Pitch}_{t_{0}} \right)}{\cos\left( {Yaw}_{j} \right)}} \\{\sin\left( {Pitch}_{j} \right)}\end{bmatrix}},{and}$ $Z_{bj} = \begin{bmatrix}{{{\sin\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\sin\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}}} \\{{{- {\sin\left( {Roll}_{j} \right)}}{\sin\left( {Yaw}_{j} \right)}} - {{\cos\left( {Roll}_{j} \right)}{\cos\left( {Yaw}_{j} \right)}{\sin\left( {Pitch}_{j} \right)}}} \\{{\cos\left( {Roll}_{j} \right)}{\cos\left( {Pitch}_{j} \right)}}\end{bmatrix}$

Roll_(j), Yaw_(j) and Pitch_(j) are the angles sampled at the samplingtime j by the tri-axial magnetometer.

After confirmation of the actual acceleration at each sampling time, theactual velocity and position can be then confirmed. Thus, the motionparameter confirming unit 540 may further comprise a velocity confirmingunit 544 and a position confirming unit 545.

The velocity confirming unit 544 is configured to obtain a real-timevelocity at the current sampling time by performing integral to theactual acceleration a_(m) ^(Mcur) from the motion original time t_(o) tothe current sampling time.

The position confirming unit 545 is configured to obtain a position atthe current sampling time by performing integral to the real-timevelocity from the motion original time t_(o) to the current samplingtime.

At least one of the acceleration, real-time velocity and position ateach sampling time between the motion original time t_(o) to the motionend time t_(e) is stored in the database as the motion parameters of themotion.

After the motion parameters are confirmed by the process shown in FIG. 4and the apparatus in FIG. 5, further application can be described asfollows:

(1) The motion parameters of the motion, such as information ofacceleration, velocity and position, can be sent to a motion recognizingdevice (such as the motion recognizing device 140 in FIG. 1 a). Themotion recognizing device can recognize the motion type of the motionaccording to the motion parameters, and thus extracting a part of themotion parameters corresponding to a certain type of sport motion. Forexample, the MEMS sensor can be disposed on a golf glove, and the methodand apparatus of the present disclosure can be utilized to confirm themotion parameters of the golf glove. These motion parameters are thenprovided to the motion recognizing device. As it is possible that thegolfer may do something other than the swing motion, such as drinkingwater, taking a rest, or picking up a phone call, the motion recognizingdevice may recognize and extract the part of motion parameterscorresponding to a full golf swing.

(2) The motion parameters such as velocity or position can be sent to aparameter display device (such as the parameter display device 150 inFIG. 1 a). The parameter display device can display the positioninformation at each sampling time in the format of a table, or display athree-dimensional motion path of the recognized object, and/or displaythe velocity information at each sampling time in the format of a tableor display the velocity information of the recognized object in a linechart. A user can check the detailed information of the motion of therecognized object, such as real-time velocity, position, position-timedistribution, and velocity-time distribution, by the parameter displaydevice.

(3) The motion parameters of the motion can be sent to an expertevaluation device, or the information displayed on the parameter displaydevice can be provided to the expert evaluation device for evaluation.The expert evaluation device can be a device performing automatedevaluation according to preset motion parameter database. The presetmotion parameter database stores evaluation information corresponding tothe motion parameters, and can provide evaluation for information suchas acceleration, real-time velocity and position at each time. Theexpert evaluation device can also be a user interface to provide themotion parameters to the expert for human evaluation. Preferably, theuser interface can obtain the evaluation information input by theexpert, and the evaluation information can be sent to a terminal devicefor the user to check for reference.

(4) The motion parameters of the motion can be sent to more than oneterminal device, such as the iPhones of more than one users. Thus, theusers of the terminal devices can share the motion parameters to createinteraction.

It should be noted that, in the embodiments of the invention, the MEMSsensor device is provided as an example of the sensor device. However,the invention is not limited to the MEMS sensor device, and other sensordevice can be utilized to perform sampling of the motion data in theembodiments of the invention.

The preferred embodiments of the present invention have been disclosedin the examples to show the applicable value in the related industry.However the examples should not be construed as a limitation on theactual applicable scope of the invention, and as such, all modificationsand alterations without departing from the spirits of the invention andappended claims shall remain within the protected scope and claims ofthe invention.

What is claimed is:
 1. A method of ball game motion recognition, comprising: obtaining and storing motion data at each sampling time, the motion data comprising: acceleration of a recognized object, angular velocity of the recognized object, and an angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system; performing motion static detection utilizing the acceleration stored at each of the sampling time to confirm a motion original time t_(o) and a motion end time t_(e) of a motion; confirming an original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o) according to the angle stored at the motion original time t_(o); and using each of the sampling time sequentially as a current sampling time to perform the steps of: confirming and recording a stance change matrix T_(bInit) ^(bCur) from the current sampling time to the motion original time t_(o) according to the angular velocity stored at the current sampling time and at a previous sampling time, and a stance change matrix T_(bInit) ^(bPre) from the previous sampling time to the motion original time t_(o); confirming a stance matrix T_(m) ^(bCur) at the current sampling time corresponding to the three-dimensional geomagnetic coordinate system as T_(m) ^(bCur)=T_(m) ^(bInit)T_(bInit) ^(bCur); and obtaining an actual acceleration a_(m) ^(Mcur) at the current sampling time by adjusting the acceleration a^(Cur) at the current sampling time utilizing the stance matrix T_(m) ^(bCur) to reduces an acceleration of gravity {right arrow over (g)} from the acceleration a^(Cur) at the current sampling time.
 2. The method as claimed in claim 1, further comprising, after obtaining and before storing the motion data at each sampling time, at least one of: performing interpolation processing to the motion data obtained at each of the sampling time; and performing filtering processing to the motion data obtained at each of the sampling time.
 3. The method as claimed in claim 1, further comprising, after obtaining and before storing the motion data at each sampling time: performing data calibration to the motion data at each of the sampling time utilizing a zero drift {right arrow over (ω)}₀ of a tri-axial accelerometer sampling the acceleration.
 4. The method as claimed in claim 1, wherein the storing of the motion data further comprises: storing most recently obtained number N of the motion data to a cache; wherein N is an integer of 3 or higher, and the motion data in the cache is in an order of the sampling time with the motion data of a latest sampling time at an end of a queue in the cache.
 5. The method as claimed in claim 1, wherein performing motion static detection further comprises: performing judgment according to predetermined motion time confirming tactics to each of the sampling time in sequence of the sampling time, if at the sampling time t_(o) the predetermined motion time confirming tactics are satisfied and at the sampling time t_(o)−1 the predetermined motion time confirming tactics are not satisfied, confirming the sampling time t_(o) as the motion original time; and if at the sampling time t_(e) the predetermined motion time confirming tactics are satisfied and at the sampling time t_(e)+1 the predetermined motion time confirming tactics are not satisfied, confirming the sampling time t_(e) as the motion end time.
 6. The method as claimed in claim 5, wherein the predetermined motion time confirming tactics comprises: confirming one of the sampling time t_(x) as motion time if a modulated variance a_(v) of the acceleration from a number T of the sampling time before the sampling time t_(x) is larger than or equal to a predetermined acceleration variance threshold and a modulated acceleration a₀ at the sampling time t_(x) is larger than or equal to a predetermined motion acceleration threshold, wherein the number T is a predetermined positive integer.
 7. The method as claimed in claim 1, further comprising, before confirming an original stance matrix T_(m) ^(bInit): comparing a time interval between the motion original time t_(o) and a last motion original time t′ to a predetermined time period threshold, and if the time interval is shorter than the predetermined time period threshold, confirming a stance matrix corresponding to the three-dimensional geomagnetic coordinate system at the last motion original time t′ as the original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o), and not confirming an original stance matrix.
 8. The method as claimed in claim 1, wherein confirming and recording a stance change matrix T_(bInit) ^(bCur) further comprises: confirming the stance change matrix T_(bPre) ^(bCur) from the previous sampling time to the current sampling time according to the angular velocity data stored at the current sampling time and at the previous sampling time; and obtaining the stance change matrix T_(bInit) ^(bPre) from the previous sampling time to the motion original time t_(o), and confirming a stance change matrix T_(bInit) ^(bCur) from the current sampling time to the motion original time t_(o) as T_(bInit) ^(bCur)=T_(bInit) ^(bPre)T_(bPre) ^(bCur).
 9. The method as claimed in claim 8, wherein the step S411 further comprises: confirming the angular velocity data w_(P) stored the previous sampling time is w_(P)=[ω_(Px),ω_(Py),ω_(Pz)]^(T) and the angular velocity data w_(C) at the current sampling time is w_(C)=[ω_(Cx),ω_(Cy),ω_(Cz)]^(T); and confirming the stance change matrix T_(bPre) ^(bCur) from the previous sampling time to the current sampling time as T_(bPre) ^(bCur)=R_(Z)R_(Y)R_(X), wherein R_(Z) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Pz)+ψ_(Cz))t/2 around a Z-axis, R_(Y) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Py)+ω_(Cy))t/2, around a Y-axis, R_(X) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Px)+ω_(Cx))t/2 around a X-axis, and t is a time interval between adjacent sampling time.
 10. The method as claimed in claim 1, wherein obtaining an actual acceleration further comprises: obtaining the actual acceleration a_(m) ^(Mcur) at the current sampling time as a_(m) ^(Mcur)=T_(m) ^(bCur)a^(cur)−{right arrow over (g)}, wherein {right arrow over (g)} is the acceleration of gravity under the three-dimensional geomagnetic coordinate system.
 11. The method as claimed in claim 10, wherein the acceleration of gravity {right arrow over (g)} can be confirmed by: obtaining the acceleration and the angle sampled from a nonmoving object with M numbers of consecutive sampling time; and confirming the acceleration of gravity {right arrow over (g)} under the three-dimensional geomagnetic coordinate system as ${\overset{\rightarrow}{g} = {\frac{1}{M}{\sum\limits_{j = i}^{i + M}{\overset{\rightarrow}{a}}_{mj}}}};$ wherein M is a predetermined positive integer, i is an original sampling time for sampling of the nonmoving object, {right arrow over (a)}_(mj)=T_(mj) ^(b){right arrow over (a)}_(bj), {right arrow over (a)}_(bj) is the acceleration sampled from the nonmoving object at one of the sampling time j, and T_(mj) ^(b) is a stance matrix of the nonmoving object at the sampling time j confirmed by the angle of the nonmoving object at the sampling time j.
 12. The method as claimed in claim 1, further comprising, after obtaining an actual acceleration: performing integral to the actual acceleration a_(m) ^(Mcur) from the motion original time t_(o) to the current sampling time to obtain a real-time velocity at the current sampling time, and performing integral to the real-time velocity from the motion original time t_(o) to the current sampling time to obtain a position at the current sampling time.
 13. An apparatus for confirming motion parameters, comprising: a motion data obtaining unit to obtain motion data at each sampling time of a motion, the motion data comprising: acceleration of a recognized object sampled by a tri-axial accelerometer, angular velocity of the recognized object sampled by a tri-axial gyroscope, and an angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system sampled by a tri-axial magnetometer; a data storage unit to store the motion data; a motion static detecting unit to perform motion static detection utilizing the acceleration stored in the data storage unit at each of the sampling time to confirm a motion original time t_(o) and a motion end time t_(o) of the motion; an original stance confirming unit to confirm an original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o) according to the angle stored in the data storage unit at the motion original time t_(o); and a motion parameter confirming unit to confirm the acceleration at each of the sampling time by using the sampling time after the motion original time t_(o) and before the motion end time t_(o) sequentially as a current sampling time; wherein the motion parameter confirming unit comprises: a stance change confirming module to confirm and record a stance change matrix T_(b) ^(bCur) from the current sampling time to the motion original time t_(o) according to the angular velocity stored in the data storage unit at the current sampling time and at a previous sampling time, and a stance change matrix T_(bInit) ^(bPre) from the previous sampling time to the motion original time t_(o); a real-time stance confirming module to confirm a stance matrix T_(m) ^(bCur) at the current sampling time corresponding to the three-dimensional geomagnetic coordinate system as T_(m) ^(bCur)=T_(m) ^(bInit)T_(bInit) ^(bCur); and a degravitation module to obtain an actual acceleration a_(m) ^(Mcur) at the current sampling time by adjusting the acceleration a^(Cur) at the current sampling time utilizing the stance matrix T_(m) ^(bCur) to reduces an acceleration of gravity {right arrow over (g)} from the acceleration a^(Cur) at the current sampling time.
 14. The apparatus as claimed in claim 13, further comprising at least one of a preprocessing unit and a filtering processing unit, wherein: the preprocessing unit is configured to perform interpolation processing to the motion data obtained by the motion data obtaining unit and sent to the data storage unit; and the filtering processing unit is configured to perform filtering processing to the motion data obtained by the motion data obtaining unit and sent to the data storage unit.
 15. The apparatus as claimed in claim 13, further comprising a data calibration unit to perform data calibration to the motion data obtained by the motion data obtaining unit and sent to the data storage unit utilizing a zero drift {right arrow over (ω)}_(o) of the tri-axial accelerometer sampling the acceleration.
 16. The apparatus as claimed in claim 13, wherein the data storage unit stores most recently obtained number N of the motion data to a cache, wherein N is an integer of 3 or higher, and the motion data in the cache is in an order of the sampling time with the motion data of a latest sampling time at an end of a queue in the cache.
 17. The apparatus as claimed in claim 13, wherein the motion static detecting unit performs judgment according to predetermined motion time confirming tactics to each of the sampling time in sequence of the sampling time, and if at the sampling time t_(o) the predetermined motion time confirming tactics are satisfied and at the sampling time t_(o)−1 the predetermined motion time confirming tactics are not satisfied, the sampling time t_(o) is confirmed as the motion original time; and if at the sampling time t_(e) the predetermined motion time confirming tactics are satisfied and at the sampling time t_(e)+1 the predetermined motion time confirming tactics are not satisfied, the sampling time t_(e) is confirmed as the motion end time.
 18. The apparatus as claimed in claim 17, wherein the predetermined motion time confirming tactics comprises: confirming one of the sampling time t_(x) as motion time if a modulated variance a_(v) of the acceleration from a number T of the sampling time before the sampling time t_(x) is larger than or equal to a predetermined acceleration variance threshold and a modulated acceleration a₀ at the sampling time t_(x) is larger than or equal to a predetermined motion acceleration threshold, wherein the number T is a predetermined positive integer.
 19. The apparatus as claimed in claim 13, wherein the original stance confirming unit comprises: a motion interval comparing module to compare a time interval between the motion original time t_(o) and a last motion original time t′ to a predetermined time period threshold; and an original stance confirming module to confirm the original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o) according to the angle stored in the data storage unit at the motion original time t_(o) if the time interval is not shorter than the predetermined time period threshold, and to confirm a stance matrix corresponding to the three-dimensional geomagnetic coordinate system at the last motion original time t′ as the original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o) if the time interval is shorter than the predetermined time period threshold.
 20. The apparatus as claimed in claim 13, wherein the stance change confirming module comprises: a first stance change confirming submodule to confirm the stance change matrix T_(bPre) ^(bCur) from the previous sampling time to the current sampling time according to the angular velocity data stored at the current sampling time and at the previous sampling time; and a second stance change confirming submodule to obtain the stance change matrix T_(bInit) ^(bPre) from the previous sampling time to the motion original time t_(o), and confirming a stance change matrix T_(bInit) ^(bCur) from the current sampling time to the motion original time t_(o) as T_(bInit) ^(bCur)=T_(bInit) ^(bPre)T_(bPre) ^(bCur).
 21. The apparatus as claimed in claim 20, wherein the first stance change confirming submodule confirms the angular velocity data w_(P) stored the previous sampling time is w_(P)=[ω_(Px),ω_(Py),ω_(Pz)]^(T) and the angular velocity data w_(C) at the current sampling time is w_(C)=[ω_(Cx),ω_(Cy),ω_(Cz)]^(T), and confirms the stance change matrix T_(bPre) ^(bCur) from the previous sampling time to the current sampling time as T_(bPre) ^(bCur)=R_(Z)R_(Y)R_(X), wherein R_(Z) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Pz)+ω_(Cz))t/2 around a Z-axis, R_(Y) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Py)+ω_(Cy))t/2, around a Y-axis, R_(X) is a stance change matrix of the angular velocity data w_(P) rotating (ω_(Px)+ω_(Cx))t/2 around a X-axis, and t is a time interval between adjacent sampling time.
 22. The apparatus as claimed in claim 13, wherein the degravitation module obtains the actual acceleration a_(m) ^(Mcur) at the current sampling time as a_(m) ^(Mcur)=T_(m) ^(bCur)a^(cur)−{right arrow over (g)}, wherein {right arrow over (g)} is the acceleration of gravity under the three-dimensional geomagnetic coordinate system.
 23. The apparatus as claimed in claim 22, further comprising a gravitational motion parameter confirming unit, wherein the gravitational motion parameter confirming unit comprises: a data obtaining module to obtain the acceleration and the angle sampled from a nonmoving object with M numbers of consecutive sampling time; and a gravity acceleration confirming module to confirm the acceleration of gravity {right arrow over (g)} under the three-dimensional geomagnetic coordinate system as ${\overset{\rightarrow}{g} = {\frac{1}{M}{\sum\limits_{j = i}^{i + M}{\overset{\rightarrow}{a}}_{mj}}}},$ wherein M is a predetermined positive integer, i is an original sampling time for sampling of the nonmoving object, {right arrow over (a)}_(mj)=T_(mj) ^(b){right arrow over (a)}_(bj), {right arrow over (a)}_(bj) is the acceleration sampled from the nonmoving object at one of the sampling time j, and T_(mj) ^(b) is a stance matrix of the nonmoving object at the sampling time j confirmed by the angle of the nonmoving object at the sampling time j.
 24. The apparatus as claimed in claim 13, wherein the motion parameter confirming unit further comprises: a velocity confirming unit to obtain a real-time velocity at the current sampling time by performing integral to the actual acceleration a_(m) ^(Mcur) from the motion original time t_(o) to the current sampling time, and a position confirming unit to obtain a position at the current sampling time by performing integral to the real-time velocity from the motion original time t_(o) to the current sampling time.
 25. A motion assisting device, comprising: an apparatus for confirming motion parameters as claimed in claim 13; and a sensor device to sample the motion data of the recognized object at each of the sampling time, the motion data comprising: the acceleration of the recognized object, the angular velocity of the recognized object, and the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system.
 26. The motion assisting device as claimed in claim 25, wherein the sensor device comprises: a tri-axial accelerometer to sample the acceleration of the recognized object; a tri-axial gyroscope to sample the angular velocity of the recognized object; and a tri-axial magnetometer to sample the angle of the recognized object corresponding to a three-dimensional geomagnetic coordinate system.
 27. The motion assisting device as claimed in claim 25, further comprising: a processor to retrieve and transmit the motion data from the sensor device to the motion parameter confirming device according to predetermined transfer protocol.
 28. The motion assisting device as claimed in claim 25, further comprising: data transmit interface to send motion parameters of the predetermined ball game type recognized by the apparatus for ball game motion recognition to a peripheral device.
 29. The method of claim 1, further comprising confirming an original stance matrix T_(m) ^(bInit) corresponding to the three-dimensional geomagnetic coordinate system at the motion original time t_(o) according to the angle stored at the motion original time t_(o). 